There is known an exhaust gas purifying apparatus, in which two particulate filters supporting NOx absorbents are disposed in parallel in an exhaust pipe, and a function regeneration process of the NOx absorbent is performed to one NOx absorbent at a time by decreasing an amount of exhaust gas flowing into the NOx absorbent (see Japanese Patent No. 2727906). There is also Japanese Utility Model Application Publication No. 7-16014 as a prior art document concerning the present invention.
In the apparatus in which occlusion-reduction type NOx catalysts (hereinafter abbreviated as NOx catalysts) which are of the NOx absorbent and the like are disposed in parallel in an exhaust passage, a distance between each NOx catalyst and each injection nozzles for supplying a reducing agent cannot sufficiently be secured, and there is a possibility that the reducing agent is supplied so as to be biased toward a part of each NOx catalyst.